Rescuing Anti-tumor Responses of TCR-Td T Cells by NKG2D-stimulation

描述（由申请人提供）：过继细胞转移T细胞的基因修饰，以表达对肿瘤抗原反应的T细胞受体（TCR-Td T细胞）已成为治疗恶性肿瘤最有前途的方法之一。然而，最近的临床研究报告客观临床反应率低于30%。为这些反应提供了一个合理的解释，研究表明，在携带肿瘤的宿主中，转移的T细胞遇到以免疫抑制为特征的不适宜环境。因此，使TCR-Td CD8+ T细胞抵抗这些负面环境提示可以显著改善癌症患者的临床反应。鉴于NKG2D受体的刺激作用，我们研究了其控制CD8+ T细胞抑制的能力。我们的数据首次表明，NKG2D刺激人类TCR-Td CD8+ T细胞（类似于临床试验中使用的细胞）和小鼠CD8+ T细胞导致对TGF-抑制的完全抵抗，并增强了对黑色素瘤的治疗性抗肿瘤反应。我们的数据还表明，nkg2d激活的TCR-Td CD8+ T细胞对TGF- α抑制的抵抗伴随着TGF- α信号的两种负调节因子RGS3和PDPK1的上调。虽然这些发现描述了NKG2D在CD8+ T细胞中的新功能，但这些途径如何在NKG2D信号传导和对抑制的抗性中相互关联仍有待确定。我们假设nkg2d诱导的TCR-Td CD8+ T细胞对抑制的抗性是由PI3K、Grb2和JNK途径以及RGS3和PDPK1的联合作用介导的。因此，本提案的目的是剖析NKG2D利用的近端和远端信号通路，以赋予对TGF-的抗性并增强抗肿瘤免疫。为此，我们将使用人类和小鼠CD8+ T细胞转导来表达TCR，以对抗表达相同受体的酪氨酸酶肽/HLA-A2和h3T转基因小鼠。我们的研究提出了一个新的范式；人类CD8+ T细胞可通过NKG2D信号转录调控，实现对TGF- β的抗性。我们相信人类TCR-Td CD8+ T细胞在ACT之前可以很容易地通过NKG2D激动剂进行调节，以提高其存活和抗肿瘤治疗能力。

DESCRIPTION (provided by applicant): Adoptive cell transfer of T cells genetically modified to express a T cell receptor reactive to a tumor antigen (TCR-Td T cells) has emerged as one of the most promising approaches for the treatment of malignancies. However, recent clinical studies report objective clinical response rates lower than 30%. Providing a plausible explanation for these responses, studies have shown that, in tumor-bearing hosts, transferred T cells encounter an inhospitable environment characterized by immune suppression. Hence, rendering TCR-Td CD8+ T cells resistant to these negative environmental cues could significantly improve clinical responses in cancer patients. Given the stimulatory role of the NKG2D receptor, we investigated its ability to control CD8+ T cell suppression. Our data show for the first time that NKG2D stimulation in human TCR-Td CD8+ T cells (similar to those used in clinical trials) and mouse CD8+ T cells results in complete resistance to suppression by TGF-� and augmented therapeutic anti-tumor responses against melanoma. Our data also show that NKG2D-activated TCR-Td CD8+ T cell resistance to suppression by TGF-� is accompanied by the upregulation of two negative regulators of TGF-� signaling, RGS3 and PDPK1. While these findings depict novel functions for NKG2D in CD8+ T cells, how these pathways are interconnected in NKG2D signaling and resistance to suppression remains to be determined. We hypothesize that NKG2D-induced resistance of TCR-Td CD8+ T cells to suppression is mediated by the PI3K, Grb2, and JNK pathways and the combined effects of RGS3 and PDPK1. Thus, the objective of this proposal is to dissect the proximal and distal signaling pathways utilized by NKG2D to confer resistance to TGF-� and enhanced anti-tumor immunity. To do this, we will use human and mouse CD8+ T cells transduced to express a TCR against a tyrosinase peptide/HLA-A2 and h3T transgenic mice, which express the same receptor. Our study posits a new paradigm; human CD8+ T cells can be transcriptionally manipulated by NKG2D signaling to achieve resistance to TGF-�. We believe that human TCR-Td CD8+ T cells could be easily conditioned prior to ACT by an NKG2D agonist to enhance their survival and therapeutic anti-tumor capacity.